Various object detection systems have been proposed to warn drivers of the presence of an object in the path of a movable vehicle. Typically, such warning systems provide a suitable warning signal either audible or visual or both, upon a sensor detecting the presence of an object in the path of the moving vehicle.
Single point of failures (SPOFs) inside the sensor hardware are generally not only difficult to detect, SPOFs can also result in false targets or incorrect calculation of target parameters. It is generally considered to be too expensive to replicate the complete hardware chain of the sensor in a parallel, truly redundant way to detect such failures. However, the overall radar detecting system is often required to have more than one radar sensor. This makes it difficult or expensive to realize a high automotive safety integrity level (ASIL) at the hardware stage in a sensor development.
In consideration of the importance of the operability of such object detection systems, it may therefore be desirable for such object detection systems to include self testing capabilities.
According to U.S. Pat. No. 5,432,516 there is provided an object detection system with a self test operation which does not require additional reflecting elements and/or specific positioning of the transmitter and receiver in order to avoid interference caused by preexisting structures on the vehicle, or reliance upon signals reflected from outside the systems such as a ground surface. Further, according to U.S. Pat. No. 5,432,516 when the system is in a self test mode, the controller provides a control signal to a switch so that the object detection signals are provided to a delay unit and thereafter to an auxiliary antenna. Hence the object detection system disclosed in U.S. Pat. No. 5,432,516 requires the use of extra hardware in the form of an auxiliary antenna. Hence, there is still a need for improved self-test of a radar device.